QuickBooks Checking - "Balance Refund" Drained the Account?

We keep some money in a QuickBook Checkings account, and a week or so ago two transactions occurred which completed drained the account. One was for the balance in one of our "envelopes" while the other was for the rest. Both transactions had a description of "Balance Refund." We're not seeing that money in any of our banks, and we can't find any more information through the online app. We've only ever transferred money into this account from one of our banks and have only ever transferred money out to the state to pay taxes. I was able to get the statement for the month and I see that these two transactions are labeled as "Adjustment" rather than "Debit" or "Transfer" or something like that. We haven't received any checks in the mail as far as I can tell.

The other day we tried for an hour today to get through to support, but we keep failing the verification challenge and we're not sure what information we're not providing properly, so we've given up on that route for now. Our account is only accessible by three people, and we use MFA, etc. No other weird behavior has been spotted.

Does anybody have any clue what this is? Is this a legitimate fraudulent charge? Or is QuickBooks doing something weird here? On May 14th, we got an email saying that we needed to update information in our QB Checking account or it would be suspended in 15 days, but it didn't make sense since all of our information was already up to date, then, 5 days later, we got another email from QB saying that email was sent in error and to ignore it, so we figured it was all good. Could that be related?